Stability of seasonal influenza vaccines investigated by spectroscopy and microscopy methods

The stability of different seasonal influenza vaccines was investigated by spectroscopy and microscopy methods before and after the following stress-conditions: (i) 2 and 4 weeks storage at 25 degrees C, (ii) 1 day storage at 37 degrees C and (iii) one freeze-thaw cycle. The subunit vaccine Influvac (R) (Solvay Pharma) and the split vaccine Mutagrip (R) (Sanofi Pasteur) were affected by all stresses. The split vaccine Fluarix (R) (GlaxoSmithKline) was affected only by storage at 25 degrees C. The virosomal vaccine Inflexal (R) V (Berna Biotech) was stable after the temperature stresses but aggregated after one freeze-thaw cycle. This study provides new insights into commercial vaccines of low antigen concentration and highlights the importance of using multiple techniques to assess vaccine stability. (C) 2011 Elsevier Ltd. All rights reserved.